View Publication | CEMHTI CNRS UPR3079 Orléans France

Sacris Jeru Tambio, 'Evaluation of electrochemical performance of lithium-ion batteries and measurements of their transport properties by high-field NMR', These 1-196 (2019)

Automotive applications of Lithium ion batteries demand two key characteristics: mileage (energy) and torque (power). Energy demand can be simple achieved by increasing electrode mass loadings. However, power suffers due to that increased electrode thickness increases the path length for ion transport, which is the key limiting factor for proper functioning at high current densities. This study deals with how the different electrode parameters affect electrochemical performance especially at high current densities. Electrochemical cycling in conjunction PFG-SE NMR were done to pinpoint performance limitations and to study ion diffusion within the electrode porosity.Electrochemical measurements reveal that at low rates the intrinsic conductivity of the active material dicates performance through the polarization resistance. At high current densities, increased mass loading and obstruction from the CB-PVdF network hampers ion transport. This is best illustrated by our analytical model which relates the various electrode parameters with the maximum working rate. NMR measurements support the hypothesis that increased CB-PVdF content increases tortuosity due to any existing interactions between the electrolyte species and these additives.